【摘要】 采用"pH-调节法"共合成得到不同钒含量的V-SBA-15催化剂,通过X射线粉末衍射、N₂吸附、透射电镜、拉曼光谱、⁵¹V魔角旋转核磁共振谱、NH₃-程序升温脱附、H₂-程序升温还原等手段对催化剂进行表征,并研究了其丙烷选择氧化反应的催化活性.结果表明,V-SBA-15催化剂保持SBA-15介孔分子筛的两维六方孔道结构,低含量时钒以高分散的孤立态四面体形式存在于分子筛的骨架中,高含量时出现聚集态的氧钒八面体物种.低钒含量的催化剂具有低酸量的弱酸性位和较低温度下的还原性,在丙烷选择氧化脱氢反应中表现出较高的催化活性.更多还原

【Abstract】 V-SBA-15 catalysts with different content of vanadium were prepared through a "pH-adjusting" co-synthesis method.The catalysts were characterized with XRD,N2 sorption,TEM,Raman,⁵¹V NMR, NH₃-TPD,and H₂-TPR techniques and their catalytic activity in selective oxidation of propane was investigated. The results indicated that the V-SBA-15 catalysts exhibited the ordered hexagonal structure similar to SBA-15. For the low V-loading catalysts with high catalytic activity the vanadium species were highly dispersed and mainly 4-coordinated.With increase of the loading,the appearance of octahedral vanadium species was observed which accounted for the decrease of catalytic activity.更多还原